POWER delivered the engineering design for the demolition of an existing coal-fired circulating fluidized-bed boiler and addition of a new 150,000 lb/hr field-erected bubbling fluidized-bed boiler firing 100% biomass. Additionally, new material handling equipment and storage silos were designed for coal and biomass. POWER provided full engineering design services (mechanical, electrical, civil, structural, and air quality) while subcontracted architectural services. We worked closely with the client and contractors to evaluate methods for demolishing existing equipment in a tight plant space and installing a new custom designed field erected boiler to fit the space without interruption to plant operations. Extensive review using 3D modeling allowed for effective planning. The plant successfully remained in operation during construction, even in spite of space constraints.